Question

Most of the transpiration in tall trees occurs through

(a) Stomata (b) Lenticels

(c) Cuticle (d) Bark

Answer 1

The correct option is (b):

Explanation of the correct option:​

1. Transpiration occurs in woody trees are through lenticels.
2. This is because lenticular transpiration occurs through the bark of the woody stem.
   
3. Tall plants have a larger surface area for the woody stem and hence most of the loss of water occurs through the lenticels.
   
4. A lenticel is a porous tissue comprising cells with huge intercellular spaces.
5. These can be found in the roots of dicotyledonous flowering plants, the bark of woody stems, periderm of secondarily thickened structures.
6. These small openings in the bark enable the gaseous exchange in woody structures of the plant.

Explanation of the incorrect options:​

Option (a):

1. The stomata is ​present on the leaves as minute pores.
   
2. Stomatal transpiration is higher in most plants, even in the early stages of the tall plants.
   
3. But in tall plants the surface area of woody part is more than the leaf surfaces.

Option (c):

1. Cuticular transpiration shows the least water loss from the plants. ​
2. The woody parts do not have cuticle on them.
3. Cuticle is the waxy coating over the leaves, green stems, etc.

Option (d):

1. The bark is basically dead in nature and is very thick.
2. There is no direct exchange of gases from the bark surface.
3. The lenticels are structures present on the bark and it helps with the lenticular transpiration. ​

Final Answer: Most of the transpiration in tall trees occurs through lenticels.